Two microorganisms, namely, Moniliella tomentosa var. pollinis CBS461.67 and Aureobasidium sp. SN-G42 FERM P-8940, are known currently to be employed practically to produce erythritol.
The former is employed, for example, in methods for producing polyols in an industrial scale by means of fermentation of saccharides (Japanese Patent Publication No. 6-30591 (30591/1994), ibid 6-30592 (30592/1994), ibid. 6-30593 (30593/1994), ibid 6-30594 (30594/1994)), and in these publications methods for producing a series of polyols including erythritol are disclosed.
On the other hand, the latter is disclosed in Japanese Patent Publications 4-11189 (11189/1992) and ibid 4-635 (635/1992) in which a novel microorganism having an erythritol producing ability and a method for producing erythritol by means of fermentation using such microorganism are described.
Meanwhile, a microorganism belonging to genus Trichosporonoides was reported by Marina A. Y. Aoki et al. of the State University of Campinus in Brazil (Biotechnology Letters, Volume 15, No.4, p. 383-388, April 1993) to be employed in conversion from sucrose and glucose to erythritol, although the species is not known. According to this report, the rates of conversion from glucose to erythritol and sucrose to erythritol were as relatively high as 43.0% and 37.4%, respectively, but the saccharide concentration for such yields was as low as 10 w/v % and the cultivation thereof takes as many days as six days, indicating a poor applicability to a production in an industrial scale.
Trichosporonoides megachiliensis employed in the present invention was reported to be a new strain by G. Douglas Inglis and Lynne Sigler of the University of Alberta in Canada (Mycologia, Volume 84, No. 4, p. 555-570, 1992). Their report contained description of morphological and physiological characteristics of a strain identified as a new strain but no description of its ability of producing erythritol.
We, the present inventors, have studied the method for producing erythritol with a use of microorganisms and finally found that Trichosporonoides megachiliensis converted saccharaides such as glucose to erythritol effectively with a high yield and completed the present invention.